1. Recognition of helical kinks by xeroderma pigmentosum group A protein triggers DNA excision repair
- Author
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Sylvie Briand Schumacher, Ramiro Dip, Benjamin Schuler, Ulrike Camenisch, Hanspeter Naegeli, University of Zurich, and Naegeli, Hanspeter
- Subjects
endocrine system ,Time Factors ,Xeroderma pigmentosum ,DNA Repair ,Photochemistry ,Protein Conformation ,DNA repair ,Biology ,DDB1 ,1315 Structural Biology ,Structural Biology ,1312 Molecular Biology ,medicine ,Humans ,Molecular Biology ,Replication protein A ,DNA ,10079 Institute of Veterinary Pharmacology and Toxicology ,Base excision repair ,Endonucleases ,medicine.disease ,Molecular biology ,Xeroderma Pigmentosum Group A Protein ,DNA-Binding Proteins ,Cross-Linking Reagents ,Tandem Repeat Sequences ,DNA glycosylase ,Excinuclease ,Mutation ,Mutagenesis, Site-Directed ,Nucleic Acid Conformation ,570 Life sciences ,biology ,Dimerization ,Protein Binding ,Nucleotide excision repair - Abstract
The function of human XPA protein, a key subunit of the nucleotide excision repair pathway, has been examined with site-directed substitutions in its putative DNA-binding cleft. After screening for repair activity in a host-cell reactivation assay, we analyzed mutants by comparing their affinities for different substrate architectures, including DNA junctions that provide a surrogate for distorted reaction intermediates, and by testing their ability to recruit the downstream endonuclease partner. Normal repair proficiency was retained when XPA mutations abolished only the simple interaction with linear DNA molecules. By contrast, results from a K141E K179E double mutant revealed that excision is crucially dependent on the assembly of XPA protein with a sharp bending angle in the DNA substrate. These findings show how an increased deformability of damaged sites, leading to helical kinks recognized by XPA, contributes to target selectivity in DNA repair.
- Published
- 2006
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